New emergency oxygen guideline: interview with Dr Ronan O'Driscoll

Key changes in the updated BTS Guideline for oxygen use in adult patients in healthcare and emergency settings

Monday, May 15, 2017

Dr Ronan O’Driscoll is a Consultant Respiratory Specialist at Salford Royal NHS Foundation Trust and first author of the British Thoracic Society’s Guideline for Emergency Oxygen Use in Adult Patients

Here he discusses key differences from the 2008 Guideline and new evidence that has contributed to the updated 2017 Guideline

Welcome Ronan.

As lead author of the updated BTS Guideline for Oxygen Use in Adult Patients, what are the key differences from the 2008 Guideline?

Many thanks. The most important point is that nothing has been published since 2008 that contradicts or challenges any of the key principles of the original Guideline. In other words there are no retractions.

We are delighted that a new body of evidence is showing how effective following the Guideline can be in improving patient outcomes and reducing avoidable deaths. This updated version has been extended to include more uses of oxygen, ranging from procedures requiring sedation such as endoscopy, through to use of oxygen mixtures like ‘gas and air’ - widely used in childbirth - to benefit an even greater number of patients.

We’ve also summarised the main changes in section 1.5 of the updated Guideline.

What new evidence has contributed to the update of the Guideline?

Since the 2008 Guideline, there has been strong new evidence to support many of the BTS recommendations concerning emergency oxygen therapy. Some of the most important new studies include:

One Randomised Controlled Trial and two observational studies which have strengthened decades of evidence that high concentration oxygen increases mortality in acute exacerbations of COPD. It is best to follow the BTS recommended target oxygen saturation range of 88-92% for these patients;

High concentration oxygen given to patients with heart attacks who have normal blood oxygen levels probably increases the size of the heart attack (high dose oxygen has little effect on the oxygen content of the blood in a person with a normal blood oxygen level but high dose oxygen constricts the small blood vessels within that heart and it paradoxically reduces the amount of oxygen available to the heart). Giving oxygen to patients with heart attacks was common practice until very recently;

Increasing evidence which suggests that very high blood oxygen levels in intensive care unit (ICU) patients are associated with increased death rates (this was also common practice in the past);

The same is true of patients who have survived a cardiac arrest (very high oxygen levels are associated with worse survival rates);

High concentration oxygen is associated with increased blood carbon dioxide levels (which may be harmful) in patients with asthma, pneumonia and morbid obesity;

Many patients who receive oxygen therapy require blood gas sampling. However, arterial blood gas sampling is often painful for patients. The Guideline allows the use of venous or arterialised capillary blood gas samples instead of arterial samples in many situations and recommends use of local anaesthetic when arterial gases are required for conscious patients (apart from life-threatening emergencies);

There has been further evidence supporting the use of high concentration oxygen to treat cluster headaches, an extremely painful condition that afflicts some people repeatedly;

There is increasing evidence that high flow humidified nasal oxygen is a useful treatment in many medical emergencies requiring oxygen therapy. Using this new technology may avoid the need for mechanical ventilation in some cases although larger studies will be required to evaluate this particular benefit.

Oxygen is a very important drug and should always be prescribed and monitored like any other medication. It is very beneficial to many patients, but can be harmful if misused. To stay safe and use oxygen in the most advantageous way, we urge all clinicians to adopt the updated Guideline, and to get in touch if they have any questions.